Aeroplane wing



July 18, 1933. v R. w. GRISWOLD, 20 1,918,536

AEROPLANE WING Filed Oct. 17, 1929 al ay ,9

. IN VENTOR.

Q35 JZ j J I l Y ATTORNEYS.

Patented July 18, 1933] v 1 r 1 benk f RIswo n ornLi cj i fi-I r c i iti o it AE ltoriiAnnw fid A v a it Aiipficafiifileviimbef 1925- Q i l'ie-14 0,19? i a a ticularly if a'jplurality l are irued foraccomplishing the purpose. The complica tionof structure and consequentincrease in 1 This; invention is directed to improving aeroplanes withthe purpose of making them a 35 has been proposed more safe,particularly as to the disastrous} v r weight defeats itspracticability.'This manner of structure, however, has been results arising fromstalling,orloss of lifti The lift'of an aeroplane, as iswell known,

is due to the Variations of air pressure above and'below the wing andthisvaries'with the angle ofattack-andalso asthejsqu'are of the c speedof the plane. Up to a certain point-the lifting powerincreases as'theangle of attack isincreased, but as this angle is inereased a criticalpoint is reached as between the angle of attack and the speed of theplanewhere the "lifting power practically ceases and disaster usuallyfollows. this condition when it happens close to the ground. "Thegreater portion of the lifting powerof the aeroplane wing is believed-tobe duetothe' reduced pressure above the wing, this reduced pressurebeing included in whatis usually called the boundary layer above thewing.-flThis re-;

duced pressure induces a forward, or'reverse flow of air around. thetrailing edge of the wing. In normal flighttthismeverseflow ex- 1 '2tends forward but avery slight distance, but ,asthefangle of attack isincreasedandthe speed diminished,,this reverse flow moves the wing, theboundary layer.

forward on thickens and finally reduces the'liftingpower to a pointwhere the normal flow is complete-v .ly broken "down" causingiwhat isusually termed burbling in the boundary layerwith resultant loss oflift'and complete loss of con propeller, 4 the tail, 5 thehorizontal'stabilizl er, 6 elevators, 7 the rudder, 8 .thefifin or ver:5

trol and the difliculties attendingthereto. It to avoid this difficultyby opening passages from the bottom of the wing to the top of the wingto create an aux;

iliary air flow to neutralize, or prevent this I increase in reversemovement andthickening 4 of the boundary layer and to restore the normalair flow over the top surface and to thus avoid the burbling action andthe loss of lift While such passages will accomplish this re-&

sult they produce an abnormal drag in nor-t '45 mal flight. To avoidthis, it has been proposed to make the wing in sections and open thesectionsto produce the passages and to close thesections in normalflight. This leads to many complications in structure and reducesverymaterially the wing strength, parutilized when eonfinedto asingle slotadjacent to the,

leading edge ofthie wing. Thepresentinveritionis designed tocorrectxinan efficient man? nerthedifiiculty as to air flow 'with'the angle: 5

of, attackrabove the critical of the normal 6 I and details of theinvention will appear, from c the'specificationfand'claims; 1f f I I; I,pe v A preferred embod ment of theiinvent n' U is illustrated-intheaccompanying drawing as v follows i Fig; '1 is a cross sec-tionofza wingon the a: Fig. 2 similarviewwith the position.

closure plates, a a

Fig.4 a plan view ofjthe' plane. i r

Fig. '5 a detail of thecontrolconnections. 1 1 marks the fuselage, 2 theengine, 3 the frame structure.

The leading edge 15Jis'preferably'movably mounted on the wing structureby means of links 16 pivotally mounted at 17 on the frame, p

theupper ends of the links being connected= at 18 to a projection 19 onthe movablelead- 5 j ing edge. As this edge swings forward it p opens aslot'20 which slotpermitsof "aimove ment of, air through the slotso'asto obviate" if the difliculties encountered when the angled"? hefront and remorse, f

present invention proaperspectiveviewof 1 i H IM O This; inventionpermitsof theluse of a conventional] 51.,

of attack is above the critical. The action of such a "slot at theleading edge iswell known and does, to some extent, correct thedifficulty encountered when the angle of at- 'stricted toward the topand are inclined upwardly towardthe rear so that the air passing vthrough them rapidly increases in velocity as it passes through the slotand emerges at the upper side of the plane at high velocity, The eifectof this is to reduce the pressure at the upperjsurface of the plane toprevent the 7 forward movement of the return flow around in presentconstruction.- Al Closure plates 22:

the-trailing edge of the planeand to avoid the creation of the burblingaction-as the angle of attack rises above the critical point of thenormal airfo'il. Thisactiontends to" stabilize the aeroplane-and.permits thec'ontinuancef of lifting force at speeds-Well be low thosefofthemnormal airfoil and while thQIG'lS a rearward movement of the centerof pressure on the wingthis rearward motioninthe absence of theburblingaction above thewing sreallya stabilizer rather than one creating thelossof control incident tostalling are pivotallv mounted at-23 on rods23a along one-edge of the bottoms'of "the slots. The

' rods-23o are mounted, in the frame. These I normal flight.

closure plates' whenin closedposition, as

shown in vFig. 1, present a lower: surface similar to the lowersurfaceof the normal plane and, :therefore, create I practically" nodrag-in The upper ends of the slotsare' so restricted. and so' inclinedas to present,

practicallyno drag in normal flight, particula'rly as they'lead into theboundary layer.

v Links 24 lead from the closure plates and are connected with links 25;The links 25 are pivotally mounted at 26 on'brackets 26a arranged intheframe; The links 2tand. 25

tending through the Wing are pivotally connected at-27a to controlrods Iv v 27 extendingforward and aft of the w ng, the forward ends ofthelinks 27 being pivotally connected at'28 to links 16. .Preferablythere is one of the link systems including the links. 24, 25 and controlrod 27 at each compression strut of the frame of the wing. The

closure plates. I'prefer, however to provide in, additionto suchautomatic control a-man-' ual control for this-purposes Bell cranks 29are pivotally mounted on the frame at points 30, one for each of thecontrol rods 27, with push and pull rods 31leading by connectionsito thecockpit. Arms 32.;of these leading edge will open" automatically and ifof sufficient power will open and close the bell cranks are connected bylinks-33 with the 2 3131181950 thatas the push and pull rods 31 aremoved theleading edge and the closure plates are actuated wTh e 31extend to both bell crank sides of theplane v and the push-and pull rodslevers 29v are, so arranged thatall j the slots are opened,orelo'sed;simultaneously.

Itwill be noted-thatthe links-.2 i'and-25 are brought into alineme-ntasthe plates" 22 are closed-,thus' securely lockinglthein in closedposition Twithout furtherstrain-on the rod 27. VhatIclaim'asIneWis 5 1.vAn aeroplane wing-having aymovable" leading edge, and provided with 1slots eX-"- from top to bot-v tomlwithj the p'ortion's..totheqfro'n'tand rear of the slot relatively rigid slots; and-aconnection. between, the closure and themov'able leading "edge opening-s-aid slots as'the leading'edge is moved forward on the swing.

; closures for said 2. An aeroplane wing.having a: rnovable leading edgeand having a slot extending through the; wingfrom'top to bottom with theportionsto the front Jandrear-of the slot t relatively rigid; a closurefor said slot; and

a connection between-the closure and the m'ovable leading edge open-mgsaid slotas the leading edge is moved forward ontherwingz r ROGERGBISWOLD

